A method for growing strained Si layer and relaxed SiGe layer with multiple Ge quantum dots (QDs) on a substrate is disclosed. The method can reduce threading dislocation density, decrease surface roughness of the strained silicon and further shorten growth time for forming epitaxy layers than conventional method. The method includes steps of: providing a silicon substrate, forming a multiple Ge QDs layers; forming a layer of relaxed SixGe1-x; and forming a strained silicon layer in subsequence; wherein x is greater than 0 and less than 1.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A forming method of strained silicon substrate, comprising the steps: providing a silicon substrate; forming a silicon buffer layer; forming a uniform silicon-germanium buffer layer with multiple germanium quantum dots upon the silicon buffer layer; forming a Si x Ge 1-x layer upon the uniform silicon-germanium buffer layer, wherein 0<x<1; and forming a strained silicon layer upon the Si x Ge 1-x layer; wherein the uniform silicon-germanium buffer layer is a multilayer with at least one silicon layer; and the uniform silicon-germanium buffer layer has a threading dislocation density less than 5×10 5 cm −2 .
2. The forming method as claimed in claim 1 , wherein the uniform silicon-germanium buffer layer has a density of germanium quantum dots ranged between 10 10 cm −2 and 10 11 cm −2 .
3. The forming method as claimed in claim 1 , wherein a space between silicon-germanium quantum dots in the uniform silicon-germanium buffer layer ranges between 10 nm and 50 nm.
4. The forming method as claimed in claim 1 , wherein a thickness of silicon layer in the uniform silicon-germanium buffer layer ranges between 30 nm and 50 nm.
5. The forming method as claimed in claim 1 , wherein the Si x Ge 1-x layer has a thickness ranged between 200 nm and 1000 nm.
6. The forming method as claimed in claim 1 , wherein the uniform silicon-germanium buffer layer is formed by chemical vapor deposition (CVD), ultra-high vacuum CVD, or molecular beam epitaxy (MBE).
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
July 20, 2006
March 3, 2009
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.